let name = '小明'
let age= 18
let flag = true

function sum(num1,num2){
  return num1 + num2
}

if(flag){
  sum(20,30);
}

// 导出方式一
export {
   flag,sum
}

//导出方式二
export var num1 = 1000;
export var height = 1.88

//导出函数/类
export function mul(num1,num2){
  return num1 + num2
}
export class Person{
  run() {
    console.log('在奔跑');
  }
}

//export default
export const address = '北京市'